The composition of metal organic framework materials and conductive polymers has attracted much attention in the field of materials, and theoretical calculations play an indispensable role in understanding the micro-structure and adsorption mechanism of the new materials. The pyrrole adsorption onto MIL-101 was saturated by dipping method, and the drying time of MIL-101/Py was controlled to regulate the content of pyrrole in the cavity of MIL-101 by taking advantage of the volatile characteristics of pyrrole at room temperature. This lays the foundation for the precise design of MIL-101 aperture. Combined with molecular dynamics simulation, it is found that at low loading, pyrrole monomers are distributed on the edge of MIL-101 cage, and gradually aggregated towards the center as the loading increases, while it is difficult for pyrrole monomers to enter when the loading is too large. Simulation auxiliary experiments show that filling of polymer monomers in MIL-101 can optimize the pore structure, and the MOF/polymer composite lays the foundation for ion-selective separation based on the pore size sieving effect. The interaction between MIL-101 and pyrrole was explored by DFT method. The order of the adsorption strength of each part in MIL-101 towards pyrrole is Cr3O-O>Cr3O-F>CH-π/NH-π>Cr3O-Cr, and judged by the adsorption energy, the adsorption between pyrrole and MIL-101 is physical adsorption.